As one of processes of manufacturing a semiconductor device, a film-forming process for forming a conductive metal film, for example, a film (W film) containing tungsten (W), on a substrate is performed in some cases. The W film may be formed, for example, by alternately performing the supply of a tungsten hexafluoride (WF6) gas to the substrate and the supply of a disilane (Si2H6) gas to the substrate a predetermined number of times (see, e.g., Patent Document 1).
In the case where a metal film is formed using a fluorine (F)-containing gas such as a WF6 gas or the like, there is a possibility that F may remain in the metal film thus formed. When a thermal diffusion step or the like is performed thereafter, the F remaining in the metal film diffuses toward a silicon oxide film (SiO2 film) or the like as a base formed in advance on the substrate. This may deteriorate the performance of a semiconductor device. Therefore, before the formation of the metal film, a process of forming a titanium nitride film (TiN film) or the like on the base as a diffusion suppressing film (barrier film) for suppressing diffusion of F may be performed in some cases.
The present disclosure provides some embodiments of a technique for improving the characteristics of a barrier film formed on a substrate.